Study Traces Olive Cultivation in Jaén Back 2,000 Years

A two-year study into the origins of olive cultivation in Jaén concluded this summer, with the results presented at the First Conference on Oliviculture Archaeology in the provincial capital.

Using a range of techniques, including stable isotope analysis, researchers found evidence that olive cultivation in the region dates back about two millennia, with its expansion closely corresponding to the advance of the Roman Empire across the Iberian Peninsula.

By the 1st century BCE, farmers in the region may already have been systematically using organic fertilizer.

The investigation, led by researcher Eva María Montes Moya of the University of Jaén, focused on archaeological remains from ancient Roman sites in the province, including El Cerro de la Atalaya and El Cerro de los Vientos, where some of the region’s oldest olive cultivation pits have been documented.

Using stable isotope analysis, specifically carbon-13 and nitrogen-15, the researchers reconstructed more than 1,000 years of agricultural history. The work produced the first isotopic record from slow-growing woody plants in the western Mediterranean.

The analysis of archaeological remains also provided information about natural soil and water conditions and how farming practices changed over time.

According to the researchers, olive cultivation in the Iberian Peninsula spread gradually, closely following the Roman Empire’s expansion across the region.

“It is from the 1st century CE onward that we find direct evidence of olive oil production in places like Cástulo and Marroquíes Bajos,” Montes Moya said.

This period followed Rome’s conquest of the Iberian Peninsula in 19 BCE and the region’s increasing integration into the Roman Empire. Roman administrative, economic, and territorial systems would remain dominant for centuries.

Cástulo, for example, was an important Roman city in Oretania, the territory historically associated with the Oretani people. The region became an important source of commodities for the empire, including minerals and olive oil.

In addition to shedding light on the chronology of olive cultivation in Spain, the research uncovered evidence of sophisticated, organized agricultural practices.

Analysis of stable nitrogen isotopes, for example, indicated that by the 1st century BCE, farmers may already have been systematically applying organic fertilizer. Researchers said the finding suggests well-developed agricultural knowledge in the peninsula even before extensive Roman farming systems became established.

The researchers also examined environmental conditions over the period studied and found significant fluctuations in water availability from Roman times through the medieval period.

Periods of greater water availability, including the early Roman imperial period and the later Emirate and Caliphate periods, coincided with phases of more intensive olive cultivation at several sites.

Overall, however, the evidence points to persistent water limitations, conditions not unlike those faced by many of Spain’s traditional rain-fed olive groves today.

The University Institute for Research in Iberian Archaeology organized the conference, with Montes Moya serving as scientific coordinator.

Organizers said they intend the conference to be the first in a series of events aimed at bringing research on olive cultivation to a wider audience and increasing public understanding of oliviculture and its history.